Respiratory Tract Disorders

Abstract

Respiratory tract infections are the commonest cause of illness in children and occur due to infection with a wide variety of organisms whose pathogenicity varies from time to time (Editorial, 1985). The child’s age and state of immune response are also important. The immune response may be inhibited by age related immaturity or underlying disease processes such as primary or secondary immune deficiency, for example, HIV infection. The respiratory system also has a number of intrinsic defence mechanisms which are important including the anatomy of the upper and lower airway, mucociliary clearance, particularly the cilia themselves which line the respiratory tract, and reflex mechanisms inhibiting invasion of the lower respiratory tract such as the cough reflex and bronchoconstriction in the small airways. Other more general factors which affect the severity of infection include the environment where dust, air pollution and tobacco smoke are important. Lung damage due to previous infections or congenital malformations such as lung cysts may also predispose the respiratory tract to infection and malnutrition inhibits the natural response to it.